Search results for "Wave vector"
showing 10 items of 33 documents
No chiral light bending by clumps of axion-like particles
2019
We study the propagation of light in the presence of a parity-violating coupling between photons and axion-like particles (ALPs). Naively, this interaction could lead to a split of light rays into two separate beams of different polarization chirality and with different refraction angles. However, by using the eikonal method we explicitly show that this is not the case and that ALP clumps do not produce any spatial birefringence. This happens due to non-trivial variations of the photon's frequency and wavevector, which absorb time-derivatives and gradients of the ALP field. We argue that these variations represent a new way to probe the ALP-photon couping with precision frequency measuremen…
X-ray Absorption Study of Gallium Arsenide at the Ga and As K-edges
1993
We present X-ray absorption study of gallium arsenide at the Ga and As K-edges. The analysis of the X-ray absorption fine structure was done in the framework of the multiple-scattering theory. Both XANES and EXAFS regions are considered. The calculated signals are in very good agreement with experimental data. It is shown that for both edges multiple-scattering contributions are negligible for wavevector values greater than 3 Å-1, and single-scattering analysis can be used without significant loss of accuracy in that region.
Multi-scale dynamics simulations of molecular polaritons: The effect of multiple cavity modes on polariton relaxation
2021
It is included two versions of this item: the Accepted Version which is already Open Access and the Published Version which is under an embargo period till 2022-03-09.
Wave-Vector Dependence of the Dynamics in Supercooled Metallic Liquids
2020
Physical review letters 125(5), 055701 (2020). doi:10.1103/PhysRevLett.125.055701
Wave-vector analysis of plasmon-assisted distributed nonlinear photoluminescence along Au nanowires
2020
We report a quantitative analysis of the wavevector diagram emitted by nonlinear photoluminescence generated by a tightly focused pulsed laser beam and distributed along Au nanowire via the mediation of surface plasmon polaritions. The nonlinear photoluminescence is locally excited at key locations along the nanowire in order to understand the different contributions constituting the emission pattern measured in a conjugate Fourier plane of the microscope. Polarization-resolved measurements reveal that the nanowire preferentially emits nonlinear photoluminescence polarized transverse to the long axis at close to the detection limit wavevectors with a small azimuthal spread in comparison to …
Imaging Symmetry-Selected Corner Plasmon Modes in Penta-Twinned Crystalline Ag Nanowires
2011
International audience; Using dual-plane leakage radiation microscopy, we investigate plasmon propagation in individual penta-twinned crystalline silver nanowires. By measuring the wavevector content of the light emitted in the substrate, we unambiguously determine the effective index and the losses of the mode propagating in these structures. The experimental results, in particular, the unexpectedly low effective index, reveal the direct influence of the nanowire crystallinity and pentagonal structure on the observed plasmon modes. By analogy with molecular orbitals of similar symmetry, the plasmon modes are also determined numerically in good agreement with the observed values. We further…
X-ray thermal-diffuse-scattering study of soft modes in paraelectricBaTiO3
1995
Anomalous x-ray thermal diffuse scattering (TDS) from the paraelectric ${\mathrm{BaTiO}}_{3}$ has been measured as a function of temperature using synchrotron radiation. Sheets of intensities that were previously reported have been confirmed. The origin of the observed TDS intensities is attributed to the soft on-(100) TA modes and overdamped [010${]}_{\mathrm{TO}}$ mode for reduced wave vector qg0.25 and 0.25, respectively. In agreement with the previous neutron inelastic scattering experiment, our results support the notion of the one-dimensionally correlated optic motion of atoms.
Kinetics of the Formation of Ordered Domains on Surfaces: Theoretical Considerations and Monte-Carlo Simulation
1986
When an adsorbed monolayer which initially is in a disordered state is suddenly brought to a temperature in the regime of the ordered phase, domains of the ordered phase are predicted to form and grow with time t after the quench according to a power law, i.e. linear dimension L(t) ∞ tx. At the same time, the structure function S(k,t) is predicted to satisfy a scaling law, S(k,t) = S(k,tx), k being the difference between the wave vector observed in the scattering and the Bragg wave vector describing the long range order. The theoretical ideas which lead to this behaviour are briefly reviewed, and evidence from simulations of simple lattice gas models and Potts models is presented. Particula…
Size effects of static and dynamic polarization in ferroelectric thin film multilayers
2001
Abstract A thermodynamic theory for the calculation of static and dynamic polarization profiles of ferroelectric thin film multilayers is developed. The free energy functional is written down using a multilayer model in which c-domain layers of the ferroelectric material alternate with a-domain layers of a second ferroelectric materials. We assume that the interfaces are perfectly sharp and that the polarization at these boundaries is zero. The equilibrium polarization profile, its temperature and thickness dependencies were determined from the solutions of the Euler-Lagrange equations. A thickness induced ferroelectric phase transition is shown to exist and its transition temperature and c…
Scattering and Localization of Classical Waves Along a Wave Guide with Disorder and Dissipation
1993
The problem of localization of classical waves has recently attracted consider-able attention.1,2 Classical waves have, of course, been the subject of extensive research already in the last century, as emphasized by Landauer in his historical sketch.3 A variety of interesting phenomena is associated with classical waves like seismic waves, tidal waves, acoustic as well as optical waves. A major topic is the transport of energy or information by these waves. The current interest in classical waves is stimulated by the development of microelectronics with its very small structures, in particular very thin wires (as connections between the components of integrated circuits) which may (or may n…